The EvChild class

(PECL ev >= 0.2.0)

Introduction

EvChild
watchers trigger when the process receives a
SIGCHLD
in response to some child status changes (most typically when a child dies
or exits). It is permissible to install an
EvChild
watcher after the child has been forked(which implies it might have
already exited), as long as the event loop isn't entered(or is continued
from a watcher), i.e. forking and then immediately registering a watcher
for the child is fine, but forking and registering a watcher a few event
loop iterations later or in the next callback invocation is not.